Ghrelin Gene Research Articles

Molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus).

Ghrelin is a novel growth hormone (GH)-releasing peptide, which has been identified as an endogenous ligand for the GH-sretagogue receptor. The sequence and expression of ghrelin has been determined in many species. In this study, to reveal the molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus), the full-length DNA and cDNA encoding ghrelin were cloned from reindeer stomach using genome walking and rapid amplification of complementary deoxyribonucleic acid ends (RACE). The expression of ghrelin in almost all tissues was examined by real-time quantitative PCR (RT-qPCR). The 4076 bp amplicon of the ghrelin gene consisting of 4 exons and 3 introns was cloned from reindeer. Results of cDNA cloning and sequence analysis revealed that the full-length ghrelin cDNA was composed of 539 bp that included a 5'-untranslated region (46 bp), an open reading frame (ORF) (351 bp), and a 3'-untranslated region (142 bp). In addition, ghrelin was expressed in the all tissues examined, with the expression in the abomasum significantly higher than that in other tissues (p<0.05), followed by the pancreas, duodenum, testis and oesophagus. The results show that the expression of ghrelin in the reindeer gastrointestinal tract is extensive, suggesting its may have a role in regulating the digestive function.

The Ghrelin Receptor (Ghsr) Gene Polymorphism in Indonesian Local Chicken and Crossbreed Is Associated With Carcass Traits

Ghrelin receptor (GHSR) gene is candidate gene for growth performance in chicken by modulating growth hormone release from the pituitary by binding to its ligand of ghrelin. Ghrelin gene, or growth hormone secretagogue (GHS) gene, is well known as feed intake and energy homeostasis regulator in mammals and birds. The objectives of this study were to identify the polymorphism of the T1857C GHSR locus in Indonesian local chicken and to evaluate its effects on carcass traits. The gene polymorphism was identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using Hin6I restriction enzyme. Effect of genotype on carcass composition was analyzed using SAS General Linear Model (GLM) procedure. The genotyping was performed on 343 individuals including Merawang, Pelung, Sentul, Kampung, broiler (strain Cobb, parent stock), F1 crossbred of Kampung x broiler (strain Cobb, parent stock), and F2 crossbred of Kampung x broiler (strain Cobb, parent stock). All individuals were successfully amplified and were resulted in a 470 bp PCR product. This locus was polymorphic with two alleles (T and C) and three genotypes (TT, CT, and CC). The T allele and TT genotype were predominant in all populations. Individuals with CT genotype were significantly had higher live weight at 26w, carcass weight, commercial cuts weights, and muscles weights than TT genotype in F2 crossbred of Kampung x broiler population. Association of the T1857C GHSR locus-polymorphism with chicken carcass composition has been described in Indonesian chicken, providing evidence that GHSR might be an important candidate gene for chicken carcass traits.

Ghrelin gene polymorphism as a genetic biomarker for prediction of therapy induced clearance in Egyptian chronic HCV patients

Ghrelin (GHRL) has important implications for liver disease. It has anti-inflammatory effects, regulates cell proliferation, modulates the fibrogenic response and protects liver tissue. Genetic variations in the GHRL gene may play a crucial role in the development of chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we examined the association of GHRL gene polymorphisms (rs26312 and rs27647), and its serum level to virologic responses to combined sofosbuvir and Simeprevir therapy for a course of 12 successive weeks in Egyptian chronic hepatitis C (CHC) patients. METHODS: Human genomic and clinical data were collected from 100 Egyptian participants in this study, 90 HCV patients who received sofosbuvir and Simeprevir and 10 non-HCV healthy subjects. Genotyping of GHRL rs26312 and rs27647, were determined with the TaqMan qRT-PCR allele detection assay. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA). RESULTS: GHRL polymorphisms (rs26312 and rs27647) genotype distributions and allele frequencies did not differ between HCV patients and normal healthy subjects or between patient groups when compared according to the therapeutic response. In addition, we found significant lower serum GHRL levels in CHC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26312 and rs27647 polymorphisms with GHRL levels in CHC patients. We conclude that GHRL SNPs (rs26312 and rs27647) do not affect response to combined sofosbuvir and Simeprevir treatment in chronic Egyptian HCV patients.

Regulation of compensatory growth by molecular mechanism in Labeo rohita juveniles under different feeding regimes

A study was carried out to assess the regulation of compensatory growth under different restriction feeding regimes in Labeo rohita juveniles by the interaction of various feed intake and growth regulating genes. A 60 day feeding trial was conducted with five treatment groups, Control (3% body weight, bw), T1 (alternate days), T2 (0.5% bw), T3 (1% bw) and T4 (2% bw) and feeding was done for first 30 days of the trial. For next 30 days, all the treatment groups were fed at a rate of 3% bw as in the control group. There was significant (p < 0.05) difference in the weight gain among the treatment groups with lowest FCR and highest PER was found in T2 group. Ghrelin gene mRNA levels were upregulated during first 30th days of the trial with highest expression levels in the T2 group. The expression levels of leptin gene mRNA were found significantly different (p < 0.05) among the treatments, which was down-regulated during initial 30 days and upregulated as the experiment progress towards 60th day. The IGF-1 mRNA expression levels were upregulated more in liver compared to the muscle tissue. The results of the study suggest that increased ghrelin levels and decreased leptin levels lead to hyperphagia during the onset of refeeding, which further triggers the compensatory growth in L. rohita. The present study describes the molecular mechanism behind the compensatory growth following a different feed restriction regime in L. rohita which is regulated due to the interaction of different energy homeostasis and growth regulating genes.

Upregulation of Ghrelin Gene Expression in the Excluded Stomach of Obese Women with Type 2 Diabetes After Roux-en-Y Gastric Bypass in the SURMetaGIT Study.

Mechanisms of type 2 diabetes remission (T2Dr) after Roux-en-Y gastric bypass (RYGB) in obese patients appear to involve gastrointestinal hormones. The objective of this study is to explore changes in ghrelin plasma levels and ghrelin gastrointestinal gene expression (GHRL) after RYGB, and their relationships to T2Dr. In 20 obese women with T2D, before and 3months after RYGB, we assessed GHRL expression by microarray and quantitative RT-PCR in gastrointestinal biopsy samples and plasma levels of ghrelin. After RYGB, GHRL expression increased in the excluded stomach (p < 0.05) with no change in other gastrointestinal sites. There were no significant changes in ghrelin plasma levels and no correlations with T2Dr. After RYGB, over-expression of GHRL gene occurs only in the excluded stomach with no correlation to T2Dr.

Effect of Probiotic and Different Sources of Fat on Performance, Carcass Characteristics, Intestinal Morphology, Immune System, Liver Enzymes, Blood Parameters and Ghrelin Gene Expression on Broiler Chickens

Effect of Probiotic and Different Sources of Fat on Performance, Carcass Characteristics, Intestinal Morphology, Immune System, Liver Enzymes, Blood Parameters and Ghrelin Gene Expression on Broiler Chickens

In1-ghrelin splicing variant is associated with reduced disease-free survival of breast cancer patients and increases malignancy of breast cancer cells lines.

Ghrelin gene generates several variants that regulate multiple pathophysiological functions, including tumor-related processes. In1-ghrelin is a splicing variant that was previously shown to be overexpressed in breast cancer (BCa), where it correlated with proliferation markers; however, its possible association with clinical outcome of BCa patients and underlying mechanisms are still unknown. To address this issue, expression levels and clinical associations of In1-ghrelin were analyzed in a cohort of 117 BCa samples. Additionally, a battery of cellular and molecular assays was implemented using two BCa cell lines (MCF-7 and MDA-MB-231), wherein the role of In1-ghrelin on proliferation, migration, dedifferentiation and signaling pathways was explored. The results generated revealed that high expression of In1-ghrelin in BCa samples was associated with lymph node metastasis and reduced disease-free survival. Indeed, In1-ghrelin overexpression stimulated proliferation and migration in MCF-7 and MDA-MB-231 cells. Similar results were found by treating MDA-MB-231 and MCF-7 with In1-ghrelin-derived peptides. Conversely, In1-ghrelin silencing decreased proliferation and migration capacities of MDA-MB-231. Furthermore, In1-ghrelin (but not ghrelin) overexpression increased the capacity to form mammospheres in both cell lines. These effects could be associated with activation of MAPK-ERK, Jag1/Notch, Wnt/β-catenin and/or TGF-β1 pathways. Altogether, our data indicate that In1-ghrelin could play relevant functional roles in the regulation of BCa development and progression and may provide insights to identify novel biomarkers and new therapeutic approaches for this pathology.

Gender differences in ghrelin, nociception genes, psychological factors and quality of life in functional dyspepsia.

AIMto evaluate gender differences in the aspect of ghrelin, nociception-related genes and psychological aspects and the quality of life (QoL) in Korean functional dyspepsia (FD) patients.METHODSTotal of 191 persons were prospectively enrolled between March 2013 and May 2016 in Seoul National Bundang Hospital, and classified into control and FD group based on ROME III criteria. Questionnaire included assessment for dyspepsia symptoms, QoL and anxiety or depression. Preproghrelin and nociception genes in the gastric mucosa and plasma acyl/des-acyl ghrelin were measured.RESULTSLower level of plasma acyl ghrelin in FD patients compared to control was significant only in male (15.9 fmol/mL vs 10.4 fmol/mL, P = 0.017). Significantly higher mRNA expressions of nerve growth factor and transient receptor potential vanilloid receptor 1 were observed in male (P = 0.002 and P = 0.014, respectively) than in female. In contrast, female FD patients had a higher anxiety and depression score than male FD (P = 0.029), and anxiety score was correlated with epigastric pain only in female FD patients (female: Spearman rho = 0.420, P = 0.037). The impairment of overall QoL was more prominent in female FD patients than male patients (5.4 ± 0.3 vs 6.5 ± 0.3, P = 0.020).CONCLUSIONGender differences of ghrelin and nociception-related genes in male and psychological factors in female underlie FD symptoms. More careful assessment of psychological or emotional status is required particularly for the female FD patients.

Effects of starvation and refeeding on expression of ghrelin and leptin gene with variations in metabolic parameters in Labeo rohita fingerlings

A study was conducted to evaluate the effect of starvation and refeeding on ghrelin and leptin gene expression in Labeo rohita fingerlings. Further, the variations in digestive, metabolic enzymes and metabolites such as glucose, glycogen and lipids were also revealed. An experimental trial of 15days was carried out, with 7days of starvation and then refeeding up to 15days. Sampling was done at different time intervals of 0, 0.5, 1, 2, 3, 5, 7, 10 and 15th day of the experiment. The ghrelin gene expression levels increased significantly (p<0.05) up to 7th day and decreased after refeeding. Leptin levels showed the opposite trend with decline in expression levels during starvation and declined to the levels of control after refeeding. The activities of digestive enzymes protease, amylase and lipase enzymes were significantly lowest (p<0.05) on 7th day of starvation and they increased after refeeding the fishes. Hexokinase and G6PDH activities were decreased with days of starvation while LDH and G6Pase significantly increased with starvation. Glycogen showed significant (p<0.05) reduction during starvation and relapsed to the level of control after refeeding, revealing the role of glycogen stores during starvation. The present study revealed the orexigenic role of ghrelin and anorexigenic role of leptin during starvation and refeeding in L. rohita which aids in maintaining the energy homeostasis through regulating nutrient metabolism. The study also concludes that L. rohita can sustain 7 days of starvation with the aid of metabolic and endocrine regulation of energy homeostasis.

Effects of Ghrelin miRNA on Inflammation and Calcium Pathway in Pancreatic Acinar Cells of Acute Pancreatitis.

The study investigated the effects of endogenous targeted inhibition of ghrelin gene on inflammation and calcium pathway in an in vitro pancreatic acinar cell model of acute pancreatitis. Lentiviral expression vector against ghrelin gene was constructed and transfected into AR42J cells. The mRNA and protein expression of each gene were detected by reverse transcription polymerase chain reaction, Western blotting, or enzyme-linked immunosorbent assay. The concentration of intracellular calcium ([Ca]i) was determined by calcium fluorescence mark probe combined with laser scanning confocal microscopy. Compared with the control group, cerulein could upregulate mRNA and protein expression of inflammatory factors, calcium pathway, ghrelin, and [Ca]i. mRNA and protein expression of inflammatory factors increased significantly in cells transfected with ghrelin miRNA compared with the other groups. Intracellular calcium and expression of some calcium pathway proteins decreased significantly in cells transfected with ghrelin miRNA compared with the other groups. Targeted inhibition of ghrelin gene in pancreatic acinar cells of acute pancreatitis can upregulate the expression of the intracellular inflammatory factors and alleviate the intracellular calcium overload.

摂食障害の罹患感受性における食欲・体重調節物質の役割 : グレリン遺伝子多型の解析(パネルディスカッション : 肥満・摂食障害の分子機構,2006年,第47回日本心身医学会総会(東京))

摂食障害の罹患感受性における食欲・体重調節物質の役割 : グレリン遺伝子多型の解析(パネルディスカッション : 肥満・摂食障害の分子機構,2006年,第47回日本心身医学会総会(東京))

Cinnamomum osmophloeum Kanehira ethanol extracts prevents human liver-derived HepG2 cell death from oxidation stress by induction of ghrelin gene expression.

Diabetes patients associated with liver disease carry a significant risk of morbidity and mortality. Cinnamon has been reported to reduce fructose-induced oxidative stress in the rat liver. However, the mechanism by which cinnamon protects the liver in a high-saccharide environment remains to be investigated. HepG2 cells were cultured with 30 mM D-ribose to mimic the high-oxidative-stress environment, typical of a liver in a diabetic patient. Three different chemical types of C. osmophloeum ethanol extracts (CEEs) were added in HepG2 culture media and the administration of all three CEEs protected HepG2 cells from D-ribose damage and increased cell survival by approximately 20 percent. Exclusively, the transcript variant 1 of the ghrelin gene, but not variant 3, was 2-3 times induced by the addition of these CEEs. Moreover, the mRNAs of ghrelin processing enzyme, furin, and mboat4 were detected in HepG2 cells. The ghrelin hormones in the culture media were increased 4-9 times by the addition of CEEs. The protective effects of ghrelin on HepG2 cells in D-ribose environment were further confirmed by recombinant ghrelin transfection. We conclude that the CEEs induce ghrelin gene expression and protect HepG2 cells from D-ribose-induced oxidative damage through ghrelin signalling.

Abstract 3491: A role for the long non-coding RNA GHRLOS in cancer

Abstract Long non-coding RNA (lncRNA) genes are abundant in the human genome, and many are now recognized as oncogenes and/or tumor suppressors. We previously characterized the structure of GHRLOS, an antisense gene on the opposite strand of the multifunctional ghrelin gene (GHRL), however, its expression and function in disease has not been described. To this end, using The Cancer Genome Atlas (TCGA) data set, we revealed that GHRLOS is differentially expressed in a number of cancers. In particular, expression was elevated in endometrial cancer (1.2 - fold; P = 7.1 x 10-3 Welch's two-sample t-test; n = 24 vs. n = 175) and prostate cancer (1.2-fold; P = 3.7 x 10-6; n = 52 vs. n = 498) compared to normal tissues. Using qRT-PCR (and commercial cDNA panels) we confirmed that GHRLOS expression was upregulated in endometrial cancer (1.96-fold, P = 0.005 Welch’s two-sample t-test, n = 5 vs. n = 17) and prostate cancer (2.46-fold, P = 0.0045 Welch’s two-sample t-test, n = 5 vs. n = 21) compared to normal tissues. Initial studies, using siRNA designed to silence endogenous GHRLOS expression, significantly reduced cell migration in the PC3 prostate cancer cell line (0.47-fold change, P = 0.042 Kruskal-Wallis test, n = 2) conversely, preliminary data using forced GHRLOS overexpression increased migration and proliferation. Taken together, we show that the long non-coding RNA GHRLOS is differentially expressed in tumor tissue and regulates cell migration and proliferation; possibly by modulating alternative splicing of the overlapping, multifunctional ghrelin gene locus. Targeting GHRLOS could provide a valuable and novel way to target the ghrelin axis in disease. Ongoing studies aim to validate in vitro functional results in complementary mouse xenograft models and identify genes and pathways regulated by this novel lncRNA. Citation Format: Esha T. Shah, Penny Jeffery, Patrick Thomas, Inge Seim, Lisa Chopin. A role for the long non-coding RNA GHRLOS in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3491. doi:10.1158/1538-7445.AM2017-3491

Association of A-604G ghrelin gene polymorphism and serum ghrelin levels with the risk of obesity in a mexican population.

Obesity is a metabolic disorder that has a multifactorial etiology and affects millions of people worldwide. Ghrelin, a hormone coded by the GHRL gene, plays a role in human body composition and appetite. Single nucleotide polymorphisms (SNPs) of the GHRL gene have been associated with obesity and metabolic disorders. To evaluate the association of A-604G SNP of GHRL promoter region with serum ghrelin levels and the risk of obesity in a Mexican population. Two hundred and fifty individuals were enrolled and classified as obese or control subjects (CS) according to BMI. DNA samples, anthropometric measurements and biochemical parameters were obtained from all subjects. The A-604G SNP was genotyped using PCR-RFLPs technique. Ghrelin levels were measured using a commercial enzyme immunoassay. The G/G genotype was more frequent among obese individuals (p < 0.0001) when compared to CS. The G/A genotype and A allele were associated with protection against obesity (OR 0.29, p < 0.0001; OR 0.39, p < 0.0001 respectively), the A allele remained significant after adjusting for age and gender (OR: 0.25, p < 0.0001). Serum ghrelin levels were higher in obese patients (p = 0.004) than in CS, however, significance was lost after adjustment for age (p = 0.088). The G/G genotype was associated with higher levels of serum ghrelin (p = 0.02) independently of the effect of age. The G/G genotype of the A-604G SNP in the GHRL gene is associated with altered serum ghrelin levels and obesity. The A allele was also associated with protection against obesity in this study.

Р. LEU72MET MUTATION OF GHRELIN GHRL GENE IN CHILDREN WITH GASTROESOPHAGEAL REFLUX DISEASE

Gastroesophageal disease (GERD) is the one of most spread diseases that injures an esophagus. Taking into account the large number of factors that can cause GERD development already in child age, including genetic predisposition, it is necessary to analyze each of them in detail. Aim of this work was to analyze a frequency and possible association type of р. Leu72Met mutation of GHRL gene in children with gastroesophageal reflux disease. The analysis of clinical parameters and course of disease in the group of 100 schoolchildren with GERD was carried out. The molecular-genetic study of c.214C&gt;A locus of GHRL gene by CPR method (rs696217) was carried out in patients with GERD and 40 healthy children from the control group. In 82% of children with GERD was revealed a GHRL 214СС (Leu/Leu) homozygous genotype, at 58% among children from the control group. GHRL 214СА (Leu/ Met) genotype was registered three times more seldom in children of the studied group comparing with ones from the control group: 15,0% and 42,5%, respectively. It was established, that GHRL 214CС genotype presence conditions the increase of GERD development risk in 3,4 times. On the contrary, GHRL 214CА genotype manifests a reliable protective effect that is essentially decreased GERD development risk in a child at such genotype – 0,24 comparing with a conventional unit. There was established alleles and genotypes distribution of c.214C&gt;A (р.Leu72Met) locus of GHRL gene in children with GERD. GHRL 214CС genotype is associated with threefold increase of GERD risk development. Gender differences as to GERD development risk at different genotypes of ghrelin gene were established. At GHRL 214СС (Leu/Leu) genotype the relative GERD risk for boys increased in more than 6 times. There were not established any differences in alleles and genotypes distribution depending on erosive or surface inflammatory changes of a gastrointestinal tract mucosa.

Effects of endurance training and herb supplementation on tissue nesfatin-1/nucleobindin-2 and ghrelin mRNA expression

This study investigated the effects of aerobic training and extract of Pistacia-atlantica (Baneh) as a plant with rich fatty acids, on tissue nesfatin-1/nucleobindin-2 and ghrelin gene expression, plasma high- and low-density lipoprotein, tissue/plasma total cholesterol and triglyceride concentrations in female rats. 20 Wistar rats were randomly assigned to saline-control, saline-training, Baneh-control, and Baneh-training groups. The training groups were given a specific exercise on a motor-driven treadmill for 8 weeks. Nesfatin-1/nucleobindin-2 and ghrelin mRNA expressions were detected by Real-time PCR method. According to the results, the trained rats had higher nesfatin-1 mRNA expressions in liver and visceral fat and liver estradiol concentration but their liver ghrelin mRNA expressions were lower compared to the control rats. Baneh-treated rats had lower nesfatin-1 mRNA expressions in liver and visceral fat and plasma HDL-C concentration, but their plasma estradiol concentrations were significantly higher. Moreover, liver estradiol concentration and liver ghrelin mRNA expression were negatively correlated, whereas the correlation between plasma estradiol and HDL-C concentrations and nesfatin-1 mRNA expression in visceral fat was significantly positive. Generally, exercise and a high-fat diet induced changes in liver ghrelin, nesfatin-1 mRNA expression, liver estradiol level, and nesfatin-1 in visceral fat, nesfatin-1 expression in liver and visceral fat, liver glucose, plasma HDL-C, and estradiol.

Whey protein effects on energy balance link the intestinal mechanisms of energy absorption with adiposity and hypothalamic neuropeptide gene expression

We tested the hypothesis that dietary whey protein isolate (WPI) affects the intestinal mechanisms related to energy absorption and that the resulting energy deficit is compensated by changes in energy balance to support growth. C57BL/6 mice were provided a diet enriched with WPI with varied sucrose content, and the impact on energy balance-related parameters was investigated. As part of a high-sucrose diet, WPI reduced the hypothalamic expression of pro-opiomelanocortin gene expression and increased energy intake. The energy expenditure was unaffected, but epididymal weight was reduced, indicating an energy loss. Notably, there was a reduction in the ileum gene expression for amino acid transporter SLC6a19, glucose transporter 2, and fatty acid transporter 4. The composition of the gut microbiota also changed, where Firmicutes were reduced. The above changes indicated reduced energy absorption through the intestine. We propose that this mobilized energy in the adipose tissue and caused hypothalamic changes that increased energy intake, acting to counteract the energy deficit arising in the intestine. Lowering the sucrose content in the WPI diet increased energy expenditure. This further reduced epididymal weight and plasma leptin, whereupon hypothalamic ghrelin gene expression and the intestinal weight were both increased. These data suggest that when the intestine-adipose-hypothalamic pathway is subjected to an additional energy loss (now in the adipose tissue), compensatory changes attempt to assimilate more energy. Notably, WPI and sucrose content interact to enable the component mechanisms of this pathway.

Vascular Effects of Obestatin in Lean and Obese Subjects.

Obese patients have impaired vasodilator reactivity and increased endothelin 1 (ET-1)-mediated vasoconstriction, two abnormalities contributing to vascular dysfunction. Obestatin, a product of the ghrelin gene, in addition to favorable effects on glucose and lipid metabolism, has shown nitric oxide (NO)-dependent vasodilator properties in experimental models. Given these premises, we compared the effects of exogenous obestatin on forearm flow in lean and obese subjects and assessed its influence on ET-1-dependent vasoconstrictor tone in obesity. In both lean and obese participants, infusion of escalating doses of obestatin resulted in a progressive increase in blood flow from baseline (both P < 0.001). This vasodilation was predominantly mediated by enhanced NO activity, because NG-monomethyl-l-arginine markedly blunted the flow response to obestatin in both groups (both P < 0.05 vs. saline). In obese subjects, antagonism of ETA receptors by BQ-123 increased forearm flow during saline (P < 0.001) but did not induce additional vasodilation (P > 0.05) during obestatin. Circulating obestatin levels were not different between lean and obese participants (P = 0.41). Our findings indicate that obestatin causes NO-dependent vasodilation in the human circulation. This effect is preserved in obesity, where it is accompanied by reduced ET-1-mediated vasoconstriction. These latter observations make obestatin a promising target for vascular prevention in obesity and diabetes.

Glucose, amino acids and fatty acids directly regulate ghrelin and NUCB2/nesfatin-1 in the intestine and hepatopancreas of goldfish (Carassius auratus) in vitro

Ghrelin and nesfatin-1 are two peptidyl hormones primarily involved in food intake regulation. We previously reported that the amount of dietary carbohydrates, protein and lipids modulates the expression of these peptides in goldfish in vivo. In the present work, we aimed to characterize the effects of single nutrients on ghrelin and nesfatin-1 in the intestine and hepatopancreas. First, immunolocalization of ghrelin and NUCB2/nesfatin-1 in goldfish hepatopancreas cells was studied by immunohistochemistry. Second, the effects of 2 and 4hour-long exposures of cultured intestine and hepatopancreas sections to glucose, l-tryptophan, oleic acid, linolenic acid (LNA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on ghrelin and nesfatin-1 gene and protein expression were studied. Co-localization of ghrelin and NUCB2/nesfatin-1 in the cytoplasm of goldfish hepatocytes was found. Exposure to glucose led to an upregulation of preproghrelin and a downregulation of nucb2/nesfatin-1 in the intestine. l-Tryptophan mainly decreased the expression of both peptides in the intestine and hepatopancreas. Fatty acids, in general, downregulated NUCB2/nesfatin-1 in the intestine, but only the longer and highly unsaturated fatty acids inhibited preproghrelin. EPA exposure led to a decrease in preproghrelin, and an increase in nucb2/nesfatin-1 expression in hepatopancreas after 2h. These results show that macronutrients exert a dose- and time-dependent, direct regulation of ghrelin and nesfatin-1 in the intestine and hepatopancreas, and suggest a role for these hormones in the digestive process and nutrient metabolism.

Abundant ghrelin gene expression by monocytes: Putative implications for fat accumulation and obesity

Hormones encoded by the ghrelin gene, GHRL, regulate many body systems. Here, we show that GHRL is abundant in monocytes. Analysis of women subjected to bariatric surgery revealed a significant postoperative reduction of GHRL in monocytes. We hypothesise that GHRL mediates monocyte-adipocyte cross-talk in health and obesity.